Hallucinations are illusory auditory perceptions in which the patient hears voices that are not present. Hallucinations are the most common hallucinations in psychiatric clinics. Patients hear voices that can be monotonous or complex; they can be verbal, such as comments, praise, insults, reprimands, or commands, or nonverbal, such as the roar of machines, the sound of running water, or the chirping of birds. Among them, verbal hallucinations are the most common, and the hallucinated voice can be directly talking to the patient or the patient as a third party to hear the conversation of others. The content of the hallucinations is usually related to the patient and is often unfavorable to the patient, such as commenting on the patient’s words and actions, discussing the patient’s character, ordering the patient to do something dangerous, etc. Therefore, the patient is often distressed. As a result, patients are often distressed and upset, and may talk to themselves, curse to the air, refuse to drink or eat, commit suicide, or injure themselves or others. Hallucinations can be seen in a variety of mental disorders, of which commentary hallucinations, argumentative hallucinations and command hallucinations are typical symptoms of schizophrenia.